If Skoda felicia w reg battery over charging alternator been changed and no different what is the problem and how do you fix it?

In the engine bay, check and clean as necessary all the earth/ground connections between the engine and the body and the battery and the body.

You usually dont need to change whole alternator, just regulator.

Type depends on the model of your skoda

http://www.nd-skoda-Volkswagen.cz/images_zbozi/1288_1.jpg